Problem: What do the following two equations represent? $2x-y = 5$ $-10x+5y = -25$
Answer: Putting the first equation in $y = mx + b$ form gives: $2x-y = 5$ $-y = -2x+5$ $y = 2x - 5$ Putting the second equation in $y = mx + b$ form gives: $-10x+5y = -25$ $5y = 10x-25$ $y = 2x - 5$ The above equations turn into the same equation, so they represent equal lines.